1. Field of the Invention
The present invention generally relates to computer software. More specifically, the present invention relates to a rendering application configured to perform a renderer-agnostic method for representing materials independently from an underlying rendering engine.
2. Description of the Related Art
The term computer aided design (CAD) refers to a broad variety of computer-based tools used by architects, engineers, animators, video game designers, and other graphics and design professionals. CAD applications may be used to construct computer models or drawings representing virtually any imaginable two-dimensional (2D) or three-dimensional (3D) construct. A rendering application may then be used to generate an image from a CAD model. Rendering is also used to describe the process of calculating effects in a video editing file to produce final video output.
A rendering application can simulate the appearance of real-world textures, colors, surface shadows, highlights, and reflections by giving the final appearance to the models and animation. As a product, rendering applications come in many forms. Some rendering applications are integrated into larger modeling, animation, and CAD packages, while others are stand-alone applications. Functionally, the rendering process is a carefully engineered program, based on a selective mixture of techniques related to light physics, visual perception, mathematics, and software development.
Rendering applications can be implemented in hardware or software. In the case of software rendering, the actual rendering process is a computationally intensive process that is frequently used for motion picture creation. Typically, software rendering is not done in real time, i.e., rendering takes longer to render a single frame than that frame is displayed. However, software based rendering may produce very high-quality images, as the renderer is not constrained by frame-rate requirements. In contrast, real-time rendering, implemented on graphics cards with 3D hardware accelerators, is frequently used in video games and is often implemented on graphics cards with 3D hardware accelerators.
Software-based rendering engines include Maya, StudioMax, Renderman, Vray and Mental Ray, among others. Similarly, sophisticated 3D graphics APIs, such as DirectX and OpenGL, may be used to control hardware-based graphics rendering pipelines. Given this assortment or available rendering tools, each having unique advantages and disadvantages, users often desire to use one rendering engine for certain purposes and another rendering engine for other purposes For example, Mental Ray™ is a powerful ray tracing rendering tool, while RenderMan™ is known to be an efficient scan-line based rendering tool. Depending on the desired effect, the user may favor one of these rendering approaches over the other.
To switch rendering engines, however, the user must understand the interface and configuration for each rendering engine. For example, to achieve a desired rendering effect using Mental Ray, the user may have to specify which dynamic library should be loaded, specify a Mental Ray file describing an interface to a shader, and specify a set of parameters. Switching to a different rendering engine may require the user to specify a completely different set of libraries, files, and parameters particular to that rendering engine. Furthermore, the users of these rendering tools oftentimes do not have a high degree of sophistication in computer programming. For example, architects, illustrators, and engineers, who may be familiar with the desired properties of rendered surfaces (e.g., whether a painted wall surface should have a glossy or matte appearance, or how graveled a concrete pathway should appear), may nonetheless lack an understanding of the rendering settings needed to achieve these effects using a given type rendering engine.
Currently, attempts at high-level rendering frameworks do not allow for the implementation of different rendering engines. For example, Autodesk® ImageStudio™ makes use of user facades to make rendering more user-friendly. However, ImageStudio™ does not allow for the implementation of multiple renderers. Also, mental images® MetaSL™ (in conjunction with the Mental Mill® application) allows users to write a shader once, and then translate the shader into an appropriate language for rendering. However, the MetaSL™ approach makes the assumption that the same implementation can be used for multiple rendering engines. This is typically not the case. A material implementation written for a ray tracer is unlikely to run or perform well in a scanline renderer or a hardware renderer. The MetaSL™ approach also requires the programmers to us a specific abstract language, instead of the native renderer API.
Accordingly, there remains a need in the art for a renderer-agnostic method for representing materials implemented in multiple rendering engines.